/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package net.phoenix.repository.query.xpath;

import java.util.Stack;

/**
 * Jigsaw server
 * 
 * @author    <a href="shamphone@gmail.com">Li XiongFeng</a>
 * @date      2012-5-6
 * @version   1.0.0
 */
public class ConditionStack extends Stack<Stack<String>>{

	/**
	 * 
	 */
	private static final long serialVersionUID = -5837125947311386471L;
	
	public void pushFrame(){
		this.push(new Stack<String>());
	}
	
	public Stack<String> popFrame(){
		return this.pop();
	}
	
	public String pushCondition(String condition){
		return this.peek().push(condition);
	}
	
	public String popCondition(){
		return this.peek().pop();
	}
	
	/**
	 * 将顶部的条件合并，并入到第二步中
	 */
	public void merge(){
		Stack<String> top = this.popFrame();
		StringBuffer buffer = new StringBuffer("");
		while (!top.isEmpty()) {
			if (buffer.length() > 0)
				buffer.insert(0, " AND ");
			buffer.insert(0,top.pop());
		}
		this.pushCondition(buffer.toString());		
	}
	
	

}
